The present invention relates to a liquid crystal display device, and, more particularly, to an improved active matrix type of liquid crystal display device in which flicker is eliminated and the power consumption is reduced.
In an active matrix type of liquid crystal display device, on a liquid-crystal side surface of one of a pair of substrates, which are arranged to face each other in an opposed manner, while sandwiching liquid crystal material therebetween, there are formed gate signal lines, which extend in the x direction and which are arranged in parallel in the y direction, and drain signal lines, which extend in the y direction and which are arranged in parallel in the x direction. Regions which are surrounded by these respective gate lines and drain lines constitute pixel regions.
Each pixel region includes a switching element which is operated in response to a scanning signal from a one-side gate signal line and a pixel electrode to which a video signal is supplied from a one-side drain signal line by way of the switching element. Between the pixel electrode and a counter electrode, which is formed on a liquid-crystal-side surface of either one of the pair of substrates, an electric field is generated, and the optical transmissivity of the liquid crystal material is controlled in response to the electric field.
Further, one of the gate signal lines is selected in response to a scanning signal supplied from a vertical scanning driving circuit, and a video signal is supplied to each drain signal line from a video signal driver circuit at the timing of selection of the gate signal line.
In a liquid crystal display device having such a constitution, a so-called dot inversion driving method has been employed, in which, to prevent the deterioration of the liquid crystal material caused by polarization derived from applying a voltage having a direct current component to the liquid crystal material for a long time, the polarity of the voltage applied to respective liquid crystals of neighboring pixel regions is inverted (alternated), so that the polarity of the voltage applied to each liquid crystal is inverted at every frame.
Further, as a display mode of the liquid crystal display device, a dot matrix display and a character display have been known, wherein data inputted to the above-mentioned video signal driver circuit is constituted of dot-matrix data.
Still further, in a so-called transmission type liquid crystal display device, which is provided with a backlight on a back surface of a liquid crystal display panel, image display is usually performed while setting the brightness of the backlight at a fixed value.